Audio for DSLR Part 1 - Run & Gun09/13/2012
This B&H video examines a few quick and affordable ways to improve the in-camera audio on "run-and-gun" style, single-operator shoots using camera mountable mics. These mics usually plug directly into the camera's 3.5mm external mic input and mount on your HDSLR accessory shoe. Some of the microphones covered in this video include the Rode VideoMic and Stereo VideoMic Pro, the Sennheiser MKE 400 and the Azden ECZ-990. This video also touches on the limitations of your HDSLR’s Auto Gain Control, as well as possible solutions including the juicedLink DS214 Amp, Meter and AGC Disabler.
Audio for DSLR Part 2: XLR Mics
I'd like to submit one other possibility: tiny voice recorders as all-in-one lavalier systems with no wires or radio frequencies. I have been testing some recently and have gotten decent results.